Bis(biguanido-κ²N,N′)copper(II) dihydrate

In the title compound, [Cu(C₂H₆N₅)₂]·2H₂O, the Cu²⁺ cation, lying at a centre of symmetry, is coordinated by four N atoms from two bidenate ligands, forming a square-planar complex. The deprotonation of the ligand causes an increase in π-conjugation. Hydrogen bonds between solvent water and the complex help to stabilize the three-dimensional network structure.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](N-C) = 0.004 Å
• R factor = 0.040
• wR factor = 0.096
• Data-to-parameter ratio = 11.4

checkCIF/PLATON results

No syntax errors found



Alert level C
CRYSC01_ALERT_1_C The word below has not been recognised as a standard
            identifier.
            Rose
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.97
PLAT420_ALERT_2_C D-H Without Acceptor       N2     -   H2     ...          ?

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL/PC (Sheldrick, 1999); software used to prepare material for publication: SHELXTL/PC.

(I)

Crystal data

C4H12CuN10·2(H2O)	F(000) = 620
Mr = 299.81	Dx = 1.756 Mg m^−3
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 1978 reflections
a = 7.133 (3) Å	θ = 3.4–26.6°
b = 22.536 (8) Å	µ = 1.94 mm^−1
c = 7.056 (3) Å	T = 298 K
V = 1134.2 (8) Å^3	Block, rose-red
Z = 4	0.30 × 0.20 × 0.20 mm

Data collection

Bruker SMART 1K CCD area detector diffractometer	1001 independent reflections
Radiation source: fine-focus sealed tube	908 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.037
ω scan	θmax = 25.0°, θmin = 1.8°
Absorption correction: multi-scan SADABS (Sheldrick, 2000)	h = −8→3
Tmin = 0.594, Tmax = 0.698	k = −26→26
4926 measured reflections	l = −8→8

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.040	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.096	w = 1/[σ^2(Fo^2) + (0.0386P)^2 + 1.3149P] where P = (Fo^2 + 2Fc^2)/3
S = 1.20	(Δ/σ)max < 0.001
1001 reflections	Δρmax = 0.31 e Å^−3
88 parameters	Δρmin = −0.32 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.039 (3)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.4557 (5)	0.12687 (15)	0.5846 (5)	0.0227 (8)
C2	0.1838 (5)	0.08402 (14)	0.4513 (4)	0.0208 (7)
Cu1	0.5000	0.0000	0.5000	0.0223 (3)
N1	0.5333 (4)	0.17980 (13)	0.6392 (4)	0.0308 (7)
H1A	0.6464	0.1808	0.6813	0.037*
H1B	0.4689	0.2120	0.6313	0.037*
N2	0.5556 (4)	0.07793 (12)	0.5974 (4)	0.0296 (7)
H2	0.6601	0.0812	0.6574	0.036*
N3	0.2788 (4)	0.13189 (12)	0.5175 (3)	0.0225 (7)
N4	0.2531 (4)	0.03003 (12)	0.4280 (4)	0.0269 (7)
H4	0.1798	0.0049	0.3740	0.032*
N5	0.0031 (4)	0.09572 (14)	0.4089 (5)	0.0327 (8)
H5A	−0.0682	0.0680	0.3663	0.039*
H5B	−0.0409	0.1309	0.4244	0.039*
O1	0.2957 (5)	0.21264 (13)	0.1849 (6)	0.0426 (8)
H11	0.279 (6)	0.1962 (18)	0.279 (6)	0.040 (14)*
H12	0.221 (7)	0.204 (2)	0.110 (8)	0.061 (18)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0213 (17)	0.0259 (18)	0.0210 (16)	−0.0023 (14)	−0.0003 (14)	−0.0024 (14)
C2	0.0227 (17)	0.0232 (18)	0.0164 (14)	0.0017 (14)	0.0011 (14)	0.0002 (13)
Cu1	0.0240 (4)	0.0200 (4)	0.0230 (4)	0.0020 (2)	−0.0036 (2)	−0.0013 (2)
N1	0.0232 (16)	0.0240 (16)	0.0451 (18)	0.0004 (12)	−0.0092 (14)	−0.0042 (14)
N2	0.0280 (16)	0.0251 (16)	0.0356 (17)	0.0024 (12)	−0.0158 (14)	−0.0089 (13)
N3	0.0199 (15)	0.0246 (15)	0.0229 (14)	0.0009 (12)	0.0001 (11)	−0.0009 (11)
N4	0.0237 (15)	0.0237 (15)	0.0333 (15)	−0.0029 (12)	−0.0063 (13)	−0.0028 (13)
N5	0.0212 (16)	0.0314 (17)	0.046 (2)	0.0032 (12)	−0.0089 (14)	−0.0069 (15)
O1	0.0449 (19)	0.0341 (16)	0.0487 (19)	−0.0085 (14)	−0.0049 (16)	0.0115 (15)

Geometric parameters (Å, º)

C1—N2	1.316 (4)	Cu1—N4^i	1.954 (3)
C1—N3	1.352 (4)	N1—H1A	0.8600
C1—N1	1.370 (4)	N1—H1B	0.8600
C2—N4	1.323 (4)	N2—H2	0.8600
C2—N5	1.350 (4)	N4—H4	0.8600
C2—N3	1.357 (4)	N5—H5A	0.8600
Cu1—N2^i	1.927 (3)	N5—H5B	0.8600
Cu1—N2	1.927 (3)	O1—H11	0.77 (4)
Cu1—N4	1.954 (3)	O1—H12	0.77 (5)
N2—C1—N3	126.8 (3)	C1—N1—H1B	120.0
N2—C1—N1	119.4 (3)	H1A—N1—H1B	120.0
N3—C1—N1	113.7 (3)	C1—N2—Cu1	128.9 (2)
N4—C2—N5	120.6 (3)	C1—N2—H2	115.6
N4—C2—N3	126.0 (3)	Cu1—N2—H2	115.6
N5—C2—N3	113.4 (3)	C1—N3—C2	121.3 (3)
N2^i—Cu1—N2	180.00 (7)	C2—N4—Cu1	128.5 (2)
N2^i—Cu1—N4	92.14 (12)	C2—N4—H4	115.7
N2—Cu1—N4	87.86 (12)	Cu1—N4—H4	115.7
N2^i—Cu1—N4^i	87.86 (12)	C2—N5—H5A	120.0
N2—Cu1—N4^i	92.14 (12)	C2—N5—H5B	120.0
N4—Cu1—N4^i	180.0 (2)	H5A—N5—H5B	120.0
C1—N1—H1A	120.0	H11—O1—H12	112 (5)
N3—C1—N2—Cu1	8.2 (5)	N4—C2—N3—C1	−6.5 (5)
N1—C1—N2—Cu1	−170.3 (3)	N5—C2—N3—C1	173.3 (3)
N4—Cu1—N2—C1	−6.7 (3)	N5—C2—N4—Cu1	−173.7 (2)
N4^i—Cu1—N2—C1	173.3 (3)	N3—C2—N4—Cu1	6.0 (5)
N2—C1—N3—C2	−0.8 (5)	N2^i—Cu1—N4—C2	−180.0 (3)
N1—C1—N3—C2	177.7 (3)	N2—Cu1—N4—C2	0.0 (3)

Symmetry code: (i) −x+1, −y, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H12···N1^ii	0.77 (5)	2.28 (5)	3.046 (5)	173 (5)
O1—H11···N3	0.77 (4)	2.22 (5)	2.972 (4)	166 (4)
N5—H5B···O1^ii	0.86	2.31	3.094 (4)	151
N1—H1B···O1^iii	0.86	2.13	2.975 (4)	166

Symmetry codes: (ii) x−1/2, y, −z+1/2; (iii) x, −y+1/2, z+1/2.